Experiment While Making A Bouncy Ball

Amy Huntley is a former science teacher and Mom that runs a great blog where she shares activities that she has done with her family. This exploration of polymers and bouncing balls caught our eye and we were happy that Amy would share it with us. We’ve adapted it just a bit. The fun part is experimenting, and it is easy to make several of these and change up the recipe and check results. Note that this will not make a bouncy ball like you get at the grocery store, but ours bounced over a foot high and the ball has quite a unique feel to it.

Add 1/2 teaspoon of the borax solution you just made and 1 tablespoon of cornstarch to the glue. Do not stir.

Allow the ingredients to interact on their own for 10-15 seconds and then stir them together to fully mix.

Once the mixture becomes impossible to stir, take it out of the cup and start molding the ball with your hands. The ball will start out sticky and messy, but will solidify as you knead it. Once the ball is less sticky, continue rolling between your hands until it is smooth and round!

Amy adds:

“My boys loved making these “bouncy” balls. They are not super bouncy like the plastic super balls that became popular when I was a kid, but they are pretty bouncy and fun to play with. We discovered that on the carpet, they have a lot more bounce then they do on the kitchen floor. ”

These are also “temporary” bouncing balls and will lose their elasticity within a few days as they dry. Keeping your bouncy ball in a sealed bag will increase its bouncy lifespan.

The original “Super Balls” got their amazing bounce ability from compressed rubber under thousands of pounds of pressure.

How does it work?
This activity demonstrates an interesting chemical reaction, primarily between the borax and the glue. The borax acts as a “cross-linker” to the polymer molecules in the glue – basically it creates chains of molecules that stay together when you pick them up. The cornstarch helps to bind the molecules together so that they hold their shape better.

Make it an experiment
You can turn this activity into a true experiment by adjusting the amount of borax, glue, and cornstarch to get the highest bounce. You can also experiment to discover the best way to get the bouncy ball to keep its bounce over time. Have fun!

My 10 year old is making this project for his science fair. We have repeated this experiment multiple times and are unable to get the balls to bounce. They dent on the side that hits the floor, and when left overnight are flat as a pancake by morning. What are we doing wrong?

Be sure you are using white glue that is not the “washable” type. We used regular Elmers glue it our tests, and while other craft glues should work, I’m told the washable glues do not work as well. I hope that helps,

I once did it at school. so i didn’t make it my self. If u left it there it would go flat like a pancake. It also has a lot of cracks in it.

Then i did it myself. me and two friends did it. It was only yesterday. It was a science project too. Mine was the only one that worked. the two friends balls were too squishy. mine was hard and bouncy. it doesn’t bounc like one you buy from the store but it is a good balll to play with. Actually i noticed it bounced on carpet better than wood or tile or cement. Anything hard. Its better on something cushioning.

My friends and the people at school probably put too much of some ingredients so it wouldn’t work correctly. The second time worked out for me better than my friends. Lets face it store balls r better!!!(:

Just so you guys know its the cornstarch that makes it bounce less…. my school did it as a chemistry lab and found that the balls without cornstarch in them worked much better… rest of the ingredients of fine.

Your conclusion would be based on your hypothesis (what you thought would happen) If, for example) your hypothesis was that the ball would bounce, and it did not, your conclusion would be that the steps you followed did not make a ball that bounces. I hope that helps a bit.

Thanks for the questions. The ball bounces higher on the carper because carpet are more “bouncy” that a hard floor, and they add their bounciness to the ball. If the ball breaks apart when you bounce it, you should use less cornstarch and it should stick together more – also make sure you mix it up really well. Have fun!

I was hoping it would’ve been like a store ball because when I found the recipe for the polymer ball there was the translucent polymer ball picture. Oh well, I had to make it 2 times to get it perfect…the glue I use is the Tacky glue but somehow it seems hard and dry so when I mold it, the ball cracks often, do you know why?

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